1. Field of the Invention
The present invention relates to a lithography apparatus, an alignment method, and a method of manufacturing an article.
2. Description of the Related Art
As a lithography apparatus used to manufacture a semiconductor device or the like, an imprint apparatus that transfers a pattern formed on a mold serving as an original onto a substrate has received a great deal of attention, in addition to an exposure apparatus that projects the pattern of a mask serving as an original onto a substrate. In the imprint apparatus, a mold with a pattern formed on it and an imprint material supplied onto a substrate are brought into contact with each other, and the imprint material is cured in that state. The mold is separated from the cured imprint material, thereby transferring the pattern of the mold onto the substrate.
In the manufacture of a semiconductor device or the like, a step of overlaying a plurality of patterns on one substrate is necessary. For this reason, in the imprint apparatus, it is important to accurately transfer the pattern of a mold to a shot region formed on the substrate. Japanese Patent No. 4185941 proposes an imprint apparatus that employs a die-by-die alignment method as an alignment method when transferring the pattern of a mold to a shot region. The die-by-die alignment method is an alignment method of detecting marks formed in a shot region and marks formed in a mold and correcting the shift between a substrate and the mold for each shot region on the substrate.
The plurality of marks formed in the shot region sometimes individually have positional shifts due to, for example, manufacturing errors of an original used in the preceding lithography process, deformation of the marks or deformation of the entire substrate caused by a semiconductor process, and the like. In this case, when alignment between the shot region and the pattern of the original is performed based on the detection result of the marks without considering the positional shifts of the marks in the shot region, it may be difficult to accurately transfer the pattern of the original to the shot region.
Japanese Patent Laid-Open No. 2002-196476 proposes a method of aligning a shot region and an original considering manufacturing errors included in the relative positions of the pattern on the original and alignment marks on the original. In the method described in Japanese Patent Laid-Open No. 2002-196476, however, positional shifts that individually occur in the marks formed in the shot region are not taken into consideration.